Personal digital assistant devices, commonly referred to as PDA's, have recently become popular for use in organizing schedules and personal information. In order to expand the capability of such devices, various additional features have been proposed for use with the PDA's including, for example, communication devices and digital cameras. While these additional features can be incorporated into the structure of the PDA itself, it is generally preferable to provide accessory devices that can be coupled to a basic PDA via a standard interface to perform the additional functions on an as needed basis.
One problem associated with the use of such accessory devices, however, is the mismatch between the power requirements of the basic PDA and the power requirements for the additional features. The basic PDA is required to have a low power drain requirement in order to extend the useful life of its batteries. Devices such as digital cameras, however, usually consume power at a much higher rate than basic PDA's and other small consumer electronic devices. In order to prevent unnecessary draining of the batteries of the basic PDA device, it is therefore preferable to provide the accessory device with its own batteries.
Even with its own power source, however, the power requirements of the accessory device might be unnecessarily drained if the accessory device begins to draw power or is turned on as soon as it is attached to the basic PDA. It would therefore be preferable to provide a mechanism for managing the power requirements of the accessory device to conserve available battery power.
In view of the above, it is an object of the present invention to provide an accessory device for a personal digital assistant that includes intelligent power management that prevents undue draining of battery power.